The 'Hygiene Hypothesis'

What is it? The “hygiene hypothesis” was first proposed in 1989. It suggests that excessive cleanliness could be responsible for the observed increase in allergies and autoimmune diseases in developed countries over the last century. These disorders remain rare in developing nations. Where life-threatening infectious diseases remain common. And where life expectancies remain much lower than in the developed world.

Allergies occur when your immune system overreacts to allergens in the environment, or in certain foods (e.g. peanuts) and toxins (e.g. bee stings). Drugs can also trigger an allergic reaction. Symptoms range from mild swelling, watery eyes and sneezing to life-threatening anaphylaxis.

Supporters of the hygiene hypothesis believe that exposure to a variety of microorganisms early in life “teaches” the immune system how to react to foreign substances. The theory goes that when young children grow up in “sterile” environments their exposure to harmless and beneficial microorganisms as well as to pathogens is reduced.

Supposing this theory to be true, it needs to be put in proper perspective.

As infectious disease expert Dr Michael Bell puts it: “Living more sanitarily may have increased asthma, but in terms of scale and impact, that’s tiny compared with the benefit of not dying from disease for lack of hygiene”.[1]

The bottom line? A little moderation and common senseis needed!Practise and teach good personal hygiene, clean your home well, particularly areas like the bathroom and the kitchen, but don’tcloister children from all dirt. Use antibacterial cleaners in areas and situations where they are most needed. And, of course, the strictest infection control practices must still be followed in health care settings and food production facilities.